Hydrophilic pathways of waterborne acrylic resin.

The ways to make waterborne acrylic resin hydrophilic and water-soluble include: First, introducing hydrophilic functional monomers into the copolymer molecular chain, such as acrylic acid, methacrylic acid, methylene succinic acid (itaconic acid), acrylic-b-hydroxyethyl ester, acrylic-B-hydroxypropyl ester, acrylamide, methylacrylamide and glycidyl acrylate, etc. Second, partially hydrolyze the acrylate copolymer in an alkaline medium.

The selection of monomers for acrylic resin copolymers is of great significance. It is also necessary to pay attention to the magnitude of the copolymerization and homopolymerization capabilities among the monomers (i.e., the magnitude of the competitive polymerization rate).

The commonly used preparation method for waterborne acrylic resin is as follows: Firstly, acrylate monomers with polar groups are subjected to solution copolymerization with other monomers, and then neutralized with neutralizing agents and dispersed in water. Polar solvents sometimes act as chain transfer agents during the reaction process to adjust the molecular weight. Meanwhile, they remain in the copolymer system after the reaction and can be used as co-solvents.

Functional groups with carboxyl, hydroxyl, amino or epoxy groups can react with each other to cross-link and cure at high temperatures, but the curing temperature is relatively high.

Water-soluble crosslinking agents such as hexamethylmethylene melamine and water-soluble phenolic resin are added to waterborne acrylic resin. They react and crosslink with each other when heated. It can be fully cured at medium temperature.